Technical Field
The present invention relates to a device for automatically detecting and registering medical equipment such as utensils, disposables and/or surgical instruments, especially for registering surgical instruments before and after an operation, or before and after sterilization.
Description of the Related Art
In an operating room, both certain surgical instruments and a certain number of instruments may be needed to perform a surgical procedure. Typically the instruments brought into the operating room prior to an operation is counted and registered manually, to be certain that the right amount and correct instruments are available for operation. After completion of the operation, the instruments are again counted and registered manually, to ensure that no instruments are missing.
Manually registering and counting of equipment, before and after a surgery, is both time consuming and ineffective. Further, the consequence of errors may in a worst case scenario pose a life threatening situation for the patient.
Other situations exist where medical instruments need to be registered, and where a more efficient procedure will be beneficial, e.g. before and after sterilization, in or out of maintenance etc.
Radio-frequency identification (RFID) may comprise passive chips, or “tags” as it is more commonly known, which essentially are small radio transceivers powered by the electromagnetic field emitted by an antenna. The received energy is used to transmit the content of a memory. Hence, the tag itself does not comprise a power source such as a battery.
Passive RFID tags may be in sizes of millimeters, and may be reliably read from a distance of a couple of meters. However, these sizes and ranges are continuously improved. The reading range also depends on a number of factors such as surrounding material, orientation of the tag, transmission power of the antenna, number of tags etc.
In the following, RFID tags will mainly be thought of as passive RFID tags. However, most apparatuses may be realized in ways of utilizing passive as well as active RFID tags.
Providing the available instruments with an RFID tag, it is in theory possible, within a couple of seconds, to read the presence of all RFID tags, and thus all instruments present in a defined space. However, several problems occur since an instrument itself, neighboring instruments, the tray and several other things may all provide shielding, scattering and/or diffusion of the signal. This means that the precision of the registration procedure may be compromised. Thus, there is a need for inventions that will provide high precision and reliability of registering units such as medical instruments, comprising RFID.
Applications have been proposed having a plurality of reflector surfaces, such as the radio communication system disclosed in US 2006/0278706 A1 comprising a plurality of reflecting plates in a space where a plurality of RFID tags are accumulated. The reflecting plates of US 2006/02878706 direct traveling direction of the radio wave irradiated from the reader/writer towards the RFID tags. However, the method described by US 2006/0278706 performs poorly if the RFID tags are randomly distributed within the space.